US2501964A - Make and break or change-over electric switch - Google Patents

Description

.1. ROBERTS 2,501,964

MAKE AND BREAK 0R CHANGE-OVER ELECTRIC SWITCH March 28, 1950 2 Sheets-Sheet l Filed July 25, 1947 ,./HUIJIIITIQ @Iam 'am-am.

lll Lllullmm 2T'- 7 INVENTOR :L Z7 .i dof/V @negers /7 .id Zi ATTORNEYS March 2s, 1950 J. ROBERTS MAKE AND BREAK OR CHANGE-OVER ELECTRIC SWITCH Filed July 23, 1947 2 Sheets-Sheet 2 INVNTOR Jo/m/ 055,675'

'SYM 'LM/LM ATTORNEYS Patented Mar. 28, 1950 UNITED- STATES PATENT OFFICE MAKE AND BREAK OR CHANGE-OVER ELECTRC SWITCH John- Roberts, London, England 4 Claims. l

This invention relates to rotary electric fuseswitch combinations and has for its chief object the provision oi an improved and simplified form of such a fuse-switch combination which is or". rugged construction and is particularly adapted for use as a heavy duty electric fuse-switch in high-amperage circuits,

According to one feature of the present invention provision is made of a rotary electric fuse-switch combination having a rotor which carries electrically conductive contact members adapted for bridging engagement with and disengagement from two pairs of stationary electrically conductive contact members, wherein one of each pair of the stationary contact members is adapted to be connected in an electrical current circuit and the remaining contact members of the two pairs are adapted to be bridged by a stationary fuse member,and wherein th rotary and stationary Contact members are relatively disposed so as to make and break the path of current at separate points which are located to opposite sides of the fuse member so that the latter is completely isolated from the circuitconnecting contacts when the rotary switch contacts are in the disengaged or open position.

According to another feature of the invention provision is made of a rotary multi-pole electric iuse-switch combination having two pairs of stationary electrically-conductive contact members embodied in each polev of the switch, each pair of said contacts being adapted to be bridged by a rotary electrically-conductive contact memer, to make or close a circuit for one pole of an electrical current, wherein onecontact of each pair oi stationary contacts is adapted for' connection to a source of current and current load respectively and the other contacts of the two pairs are adapted to be electrically bridged by a stationary fuse-member, the said rotary and sta'- tionary contact members being relatively disposed so as to make and break the path of current through the switch pole at two separate points which are located to opposite sides of the fuse member so that the latter is completely isolated from the current-supply and current-load contacts of the switch when the rotary contacts are in the open or disengaged position.

In a form of the invention which is at present preferred the rotary contact members may be mounted upon a switch rotor which comprises a disc or drum carrying the rotary contact members upon its peripheral surface and the xed and rotary contacts are relatively disposed so as to make and break the path of current at two i' points which are located upon diametrically op` posite sides of the switch rotor.

According to another feature of the invention the disc or drum when such is used may be provided with an annular groove or plurality of annular grooves in its peripheral surface and the' rotary contact members are disposed upon the bottom of the groove or of each groove, so that the contacts are contained between walls of insulating material.

According to another feature of the invention it may also be arranged so that the contact members or strips carried by the switch rotor are let into recesses formed in the surface of such rotor and are urged outwardly therefrom by resilient means, for example, spring means.

rlhe means for effecting angular movement of the switch rotor may take various forms one 0I" which comprises a rod` or projection or projections disposed parallel with the axis of rotation of the switch rotor and caused to engage a slot therein so that by bodily displacement of the rod or projection or projections along an arcuate path the said rotor will be angularly displaced to the desired extent. The rod or projection or projections may be carried by or mounted in position upon one or more radially disposed rocker arms having resilient means associated therewith and arranged to impart a snap-over action to the rocker arm or arms in the displacement of the rod or projection or projections from one end to the other of the arcuate path of movement thereof.

Preferably, the slot or slots in the switch rotor in which the rod or projection or each projection engages is or are made arcute and elongated sufficiently to provide a lost motion coupling between the said parts so that the angular movement of the said rotor is mainly eiected by and is completed during the snap-over movement of the rocker arm or arms.

Conveniently, the radially disposed rocker arm or each of such arms may have helical spring means associated therewith and normally ten-l sioned and inclined to a radial line extending from the rod or projection to the axis o rotation of the switch rotor so as yeldingly to hold the rod or projection at one end of the arcuate slot in which it is located thereby maintaining the rod and said rotor in one positiony of angular displacement. Such spring or springs may be conveniently arranged to become further tensioned and aligned with the said radial line when the rod or projection is displaced toi the other end of its arcuate slot and to act, upon further 3 displacement of the rod or projection, to complete the movement of the latter and the said rotor to the alternative angular position oi displacement.

Furthermore, the switch rotor may be provided with an arcuate slot or slots in to which a iixed rod or projection or projections extends or extend to limit the angular displacement of the rotor to a dead beat movement.

The invention is particularly applicable to multiphase e. g. threeephase circuits and, as ap plied thereto, may be provided with a plurality say three spaced and coaxially arranged switch rotor discs or drums each having the characteristlcs out-lined and adapted to be displaced simultaneously by a single rod extending through three aligned arcuate slots, viz. one in each of the discs or drums.

In order that the invention may be fully understood and carried into effect, a constructional embodiment thereof will hereinafter be described, by way oi example, and without implied limitation by reference to the accompanying drawings in which- Figure 1 is a side elevational View of a rotary triple pole fuse-switch mechanism with the switch casing removed;

Figure 2 is a plan View thereof;

Figure 3 is a sectional View taken on line III-III of Fig. 2, showing the switch contacts in the on position;

Figure 4 is a sectional view similar to Fig. 3, but showing the switch contacts in the ofi position; and

Figures 5 and 6 are fragmentary detail views of the switch operating handle devices.

Referring to the drawings, I indicates rectangular side plates having their rear ends flanged and drilled to provide brackets 2 for attachment by screws 3 to the back of a switch casing 4 (shown in chain dot outline in Fig. 1).

Front and rear pairs of rods 5, 6 extend between the side plates I, the ends of the rods being screw-threaded and passed through holes in the plates to receive washers 1 and securing nuts 8.

The front pair of rods 5 are passed through the sides of three rectangular contact-mounting blocks 9, sp-acer sleeves l0, and longitudinal insulating shields Ii, all of which are rigidly clamped together, with the blocks 3 and screens Il in parallel, spaced relation, when the nuts 8 are screwed down upon the ends of the rods 5. In a similar manner, the inner rods E are passed through three arcuate contact-mounting blocks I2, and spacer sleeves I 3 which are clamped tightp ly together with the blocks I2 held in parallel spaced relation, when the nuts are screwed down upon the ends of rods 6. The middle rear portions of the shields il are cut away to leave a clearance -between the rear parts of the plates l.

The contact-mounting blocks 9, l2 and the associated spacer sleeves Il), i3 are all made of electrical insulating material or, at least, mainly composed of such material.

A spindle I1 is also extended between the side vplates I, intermediate the front and rear rods 5, E, the ends of the spindle being journalled in, and projecting outwards from, the plates4 Upon spindle I1 are rotatably mounted three contact carrying discs or drums Ill provided with comparatively wide peripheral flanges I9 and axial bosses or hubs 20, which latter abut to act as spacers between the adjacent drums and between the outer drums and adjacent side plates. The drums I8, which constitute the switch rotor may be made as an integral whole, or built up from two or more parts, and are preferably metal bushed.

The drums I8 are free to rotate about spindle I1y but are limited to a rocking movement by a rod 2l which is xedly secured at its ends to the side plates I, and extends therebetween as shown in Fig. 1. The rod 2l passes through arcuate slots 22 which are formed in the drums IB, the slots 22 being concentric with the axis of rotation of the drums, and disposed in axial alignment with their sides parallel to the spindle I1.

A second set oi arcuate slots 23, which are mutually aligned and disposed similarly to the slots 22 in relation to the spindle I1, but more or less diametrically opposite to the slots 22, are formed in the drums I8. A drum rocking rod 24 extends through the slots 23, the ends of the rod 24 passing freely through arcuate slots 25 which are formed in the plates I, concentric with the axis of spindle I1. The outer ends of the rod 24 enter blind roles 26 formed in the inner faces of rocker arms 21 which are mounted upon and pinned to the outwardly projecting ends of spindle I1, the rocker arms thus being locked together for simultaneous and equal movement. Spring-anchoring pins 28 are secured to, and project outwards from, the free extremities of the rocker arms 21, and similar pins 29 are secured to, and project outwards from, the side plates I in parallel relation to the pins 28. The pins 29 are located in a plane containing the axis of the spindle I1 and the centres of curvature of the arcuate slots 25 in the side plates I. Helical tension springs 30 are anchored between each pair of pins 28, 29 and are normally tensioned to hold the rocker arms 21 to one side or the other of the axial plane referred to above.

Arcuate recesses 3| are formed in diametrically opposite parts of the peripheral surface of each drum I8, and convex contact strips 32 of copper,

brass or other electrically conductive material are inserted in the recesses 3|. Blade springs 33, interposed between the contact strips 32 and convex bottom surfaces of the recesses 3l, act rer siliently to displace the contact strips outwards from the recesses 3I to a limited extent, as shown in Figs. 3 and 4.

Pairs of electrically conductive stationary contacts, which may be suitably formed, for example, of square section brass rod, are secured to the ends of the contact-mounting blocks 9. Each contact comprises a contact bar I5 carried by, and formed integral with, a post I4 which is secured to the block 9 by cheese head screws 34 which pass through the posts I4 and engage drilled and tapped metal inserts 35 set in the ends of the blocks 9.

Contact bars 36, also of square sectional metal such as brass, are secured to the flat ends of the arcuate contact mounting blocks I2 by cheese head screws 39 which engage drilled and tapped metal inserts set in the ends of the blocks. The contact bars 36 are provided with sockets 31 and set screws 38 to form terminal connections for electrical leads (not shown).

The contact bars I5, 36 are radial to the longitudinal axis of the drums I8, and extend inwards towards the drum to bring the inner ends of the stationary contact bars, which are made appropriately concave, into substantially full surface contact with the outer convex surfaces of the rotary contact strips 32. In the arrangement shown in the drawings one rotary contact strip 32 remains constantly in engagement with one of the nxed stationary contact bars I5 while the other rotary contact strip remains constantly in engagement with one of the iixed stationary contact bars 36.

The fixed contact bars I5 vare-electrically bridged by stationary cartridge fuse elements 48 which are provided with metallic connecting brackets or lugs 42; the fuse brackets being secured to the contact posts I4 by cheese head screws 4I which engage in drilled and tapped holes in the ends of the posts.

The above described mechanism when in use will be housed in a metal casing 4 complete with a removable cover (not shown) and will be'actuated by a switch arm and handle 43 (Figs. 5 and 6) pivotally mounted upon the other side of the casing 4 and connected to a rocker pin 41 upon which is mounted a pin plate 45 set within the casing 4 and carrying a pair of shift pins 46 projecting therefrom for engagement with one of the rocker arms 21.

The insulating screens II have transverse insulating shields 44 associated therewith so that each set of contact bars I5, 36 is shielded from the adjacent set or sets of contact bars by a longitudinal shield H, and the contact bars of each pair between which Contact is made and broken by the displaceable contacts, are shielded one from the other by transverse shields 44. It will be noted also that the contact ends of the respective pairs of contacts are shielded one from the other by the relative disposition thereof upon opposite sides of the drums, and are also shielded from the adjacent sets of contacts by the radially projecting flanges I9 of the drums I8.

In the operation of the switch mechanism above described, assuming that the switch is connected in an electrical circuit by leads secured in the terminal sockets 31 and that the rotary switch contacts are in the break or ofi position shown in Fig. 4, by manipulation of the switch handle 43, the shift 'pin 46 will be caused to shift the rocker arms 21 from the position corresponding to that shown in Fig. 4 towards the position corresponding to that shown in Fig. 3. In the ilrst part of this movement the rocker arms are moved against the tension of the springs 30 which thus become further tensioned and aligned with a radial line extending from axial centres of the rod 24 and pins 28 to the axis of the drums I8 and spindle I1. During this part of the movement of the rocker arms the rod 24 is displaced to the further ends of the arcuate slots 23 without moving the drums switch rotor I3. By further rocking movement of the arms 21 the tensioned springs 3G are carried past the dead centre position, and the movement oi the rocker arms 21 and rod 24 to the position shown in Fig. 3 is rapidly completed by contraction of the springs in a so-called spring-snap action. In the last part of the movement of rod 24 it carries the drums I8 round with it, and each rotary contact strip 32 rapidly moves towards, and slides into contact with, the opposite member of the make and break pair of fixed contacts I5, 35 with which it is associated, so that the gap between the said iixed contacts is bridged by the rotary contact strip. Thus, the circuit of each pole is completed over fixed terminal contacts 36, bridging contact strips 32, xed contacts I4, I5 and bridging fuse 43.

Manipulation of the switch handle 43 to eiect reverse movements of the displaceable drums and contacts with the lost motion spring-loaded coupling between the drums I8 and rod 24 will also serve to eiiect rapid or snap-action break between, the fixed andl rotary contact members. It will be realised that each pole of .the switch is thus lbroken or interrupted at two points which lie respectively to eitherr side of the -fuse member incorporated therein so that the latter is: completely visolated fromy the switch terminals 3T, i. e. the electrically alive side ofk the switch, when the switch contacts are open or in ther break position.

It will be obvious that in a modification. of the above describedr constructional embodiment of the invention, the several discs or drums I8 may, if desired, be'made integral in the form of an elongated multi-grooved, cylindrical drum.y

I claim.:

1. A rotary electric. fuse-switch comprising a support, a rotor mounted rotatably in the support, means for rotating the rotor, two pairs of rigidly mounted rigid contact blocks located around and adjacent the rotor and in a common plane therewith, stationary fuse-holding means connected to one pair of said blocks, means for connecting the other pair of blocks across a break in an electric current line, two contact members having outer convex surfaces operatively movable with and carried by the said rotor, springs carried by said rotor for urging said contact members radially outwardly from the axis of the rotor to engage the contact blocks in radial directions, said contact members being adapted to such engagement to connect a fuse-connected block with a lineconnected block on one side of the fuse and the other fuse-connected block with the other lineconnected block on the other side of the fuse, said rotor being rotatable to an off position.

2. A rotary electric fuse-switch comprising a support, an insulator rotor mounted rotatably in the support, means for rotating the rotor, a stationary fuse-carrying insulator block mounted on one side of the rotor, a stationary electric line terminal-carrying insulator block mounted on the opposite side of the rotor, a pair of rigid fuse contact blocks attached to opposite ends of the fuse-carrying block and extending on opposite sides thereof the extending ends on one side being adjacent to the rotor, and the extending parts on the other side being adapted for attachment thereto of a fuse for bridging these blocks, fusecarrying means directly attached to said parts, a pair of rigid line terminal contact blocks mounted at opposite ends of the terminal carrying insulator block and projecting on opposite sides thereof the projecting ends on one side being in proximity to the rotor and in the same plane as the fuse contact blocks and the other projecting ends being adapted for direct attachment thereto of the electric line, two contact elements having outer convex surfaces operatively movable with and carried by the rotor, springs carried by the rotor for resiliently urging said contact elements radially away from the rotor so as to be pressed rmly into contact with the contact blocks so as to connect the fuse-connected block on one side of the fuse with a line-connected block and the other fuse-connected block with the other line-connected block on the other side of the fuse, said rotor being rotatable to an oi position.

3. A rotary electric fuse-switch combination as claimed in claim 1, wherein the rotor is freely mounted on a spindle fixed in the support, said rotor having an arcuate slot therein, a rod disposed parallel to the said spindle and disposed in the slot of said rotor to engage the same so that by bodily displacement of the rod along an arcuate path the said rotor will be angularly displaced, a rocker arm carrying the rod, resilient means associated with the rod and arranged to impart a snap-over action to the rocker arm upon displacement of the rod, said slot providing a lost motion coupling between the rotor and the rod so that the angular movement of the switch rotor is mainly eiected by and is completed during the snap-over movement of the rocker arm.

4. A rotary electric fuse-switch combination as claimed in claim 1, wherein the means for rotating the rotor comprises means for engaging said rotor, and resilient means associated with said engaging means and arranged to impart a snapover action thereto, said rotor being cut away to provide a lost motion coupling between said rotor REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,224,119 Sutherland Apr. 24, 1917 1,678,336 Getchell July 24, 1928 2,002,587 Sachs May 28, 1935

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